Virus Characteristics
-- Update August 16, 2004 --
The assessment of this threat was lowered to Low-Profiled due to a decrease in prevalence.
--
-- Update August 9, 2004 --
The HTML file is detected with the 4167 (from Nov. 2001) and higher DATs as JS/IllWill. The DLL component is detected with 4335 (Mar. 2004) and higher DATs as W32/Bagle.dll.gen.
--
If you think that you may be infected with W32/Bagle.aq@MM, and are unsure how to check your system, you may
download the Stinger tool
to scan your system and remove the virus if present. This is not required for McAfee users as McAfee products are capable of detecting and removing the virus with the latest update. (see the removal instructions below for more information).
Note:
Receiving an email alert stating that the virus came from your email address is not
an indication that you are infected as the virus often forges the from address.
|
This is a mass-mailing worm which has the following characteristics:
- contains its own SMTP engine to construct outgoing messages
- harvests email addresses from the victim machine
- the From: address of messages is spoofed
- attachment is a zip file, which contains an EXE and HTML file
- contains a remote access component (notification is sent to hacker)
- copies itself to folders that have the phrase shar
in the name (such as common peer-to-peer applications; KaZaa, Bearshare, Limewire, etc)
The worm sends out a ZIP file which contains an HTML and EXE file. The EXE file is within a folder in the ZIP file so that when it's viewed with Explorer (rather than a stand-alone ZIP file handler like WinZip or PKzip) the HTML file and a separate folder is what is visible.
The HTML file contains exploit code which, on vulnerable systems, will automatically run the EXE file which is a downloader trojan. The downloader trojan then contacts a large number of remote websites to retrieve the virus itself.
Mail Propagation
The virus which is downloaded contains the propagation code. The details are as follows:
From :
(address is spoofed)
Subject :
(blank)
Body Text:
There is indication in the file that it may also try to password-protect some ZIP files, in which case it will add one of the following to the message body:
- The password is
- Password:
The password will then be contained in an embedded image file.
Attachment:
(may be one of the following)
- price.zip
- price2.zip
- price_new.zip
- price_08.zip
- 08_price.zip
- newprice.zip
- new_price.zip
- new__price.zip
The ZIP file contains PRICE.EXE and PRICE.HTML, as described above.
If the ZIP file is opened with Windows Explorer (rather than a stand-alone ZIP handler such as WinZip or PKzip) the HTML file will be visible along with a folder which contains the EXE file. When the HTML file is run on a vulnerable system, it will run the EXE file.
When the EXE file is run (either manually or automatically by the HTML file), it will copy itself to the Windows System directory as WINDIRECT.EXE. For example:
- C:\WINNT\SYSTEM32\WINdirect.exe
It also drops a DLL file in this directory:
The DLL file is injected into the Explorer.exe process, so its actions will appear to have originated from Explorer.exe.
The following Registry keys are added to hook system startup:
- HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run "win_upd2.exe" = C:\WINNT\SYSTEM32\windll.exe
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\Run "win_upd2.exe" = C:\WINNT\SYSTEM32\windll.exe
Once the virus executable is downloaded and run by the downloader trojan, the virus copies itself into the Windows System directory as WINDLL.EXE . For example:
- C:\WINNT\SYSTEM32\windll.exe
It also creates other files in this directory to perform its functions:
- C:\WINNT\SYSTEM32\windll.exeopen
- C:\WINNT\SYSTEM32\windll.exeopenopen
The following Registry key is added to hook system startup:
- HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run "erthgdr" =
"C:\WINNT\SYSTEM32\windll.exe"
Additionally, the following Registry keys are added:
A mutex is created to ensure only one instance of the worm is running at a time. One of the following mutex names is used in an attempt to stop particular variants of W32/Netsky running on the infected machine:
- 'D'r'o'p'p'e'd'S'k'y'N'e't'
- _-oOaxX|-+S+-+k+-+y+-+N+-+e+-+t+-|XxKOo-_
- [SkyNet.cz]SystemsMutex
- AdmSkynetJklS003
- ____--->>>>U<<<<--____
- _-oO]xX|-S-k-y-N-e-t-|Xx[Oo-_
The worm opens port 80 (TCP) and a random UDP port on the victim machine.